Brene Brown uses the acronym BRAVING for what makes a person trustworthy. If/when he meets these criteria, then you can consider placing your trust in him again:
B – Boundaries.  You respect my boundaries and when you are not clear about what’s OK and what’s not OK, you ask. You are willing to say no.
R – Reliability.  You do what you say you’ll do.  At work this means staying aware of your competencies and limitations so that you don’t over-promise and are able to deliver on commitments and balance competing priorities.
A – Accountability.  You own your mistakes, apologize, and make amends.
V – Vault.  You don’t share information or experiences that are not yours to share.  I need to know that my confidences are  kept and that you are not sharing with me information about other people that should be confidential.
I – Integrity.  You choose courage over comfort.  You choose what is right over what is fun, fast, or easy.  And you choose to practice your values rather than simply professing them.
N – Non-judgment.  I can ask for what I need, and you can ask for what you need.  We can talk about how we feel without judgment.
G – Generosity.  You extend the most generous interpretation possible to the intentions, words and actions of others.